66777443321 has 2 divisors, whose sum is σ = 66777443322. Its totient is φ = 66777443320.

The previous prime is 66777443303. The next prime is 66777443329. The reversal of 66777443321 is 12334477766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 60991711225 + 5785732096 = 246965^2 + 76064^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66777443321 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66777443321.

It is not a weakly prime, because it can be changed into another prime (66777443329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33388721660 + 33388721661.

It is an arithmetic number, because the mean of its divisors is an integer number (33388721661).

Almost surely, 2^66777443321 is an apocalyptic number.

It is an amenable number.

66777443321 is a deficient number, since it is larger than the sum of its proper divisors (1).

66777443321 is an equidigital number, since it uses as much as digits as its factorization.

66777443321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3556224, while the sum is 50.

The spelling of 66777443321 in words is "sixty-six billion, seven hundred seventy-seven million, four hundred forty-three thousand, three hundred twenty-one".